Conveyor belt idler rollers

ABSTRACT

A support idler roller for belt conveyors which includes a hollow shaft carrying roller bearings and a concentric roll body made up of a pair of semi-cylindrical complementary sections concentrically disposed relative to the shaft and supported in spaced relation to the shaft by the roller bearing structure and an elastic sleeve member having an outer cylindrical wear surface for supporting a belt conveyor resiliently holding the two complementary sections together, the inner bearing raceway member of the roller bearing structure being rigidly affixed to the shaft and the outer bearing raceway member being frictionally received and held by the body member, the frictional resistance between the outer bearing raceway member and the body member being such as to permit the body member to turn on the outer bearing raceway member if the roller bearing should freeze.

United States Patent [1 1 Pico [ Dec. 30, 1975 [54] CONVEYOR BELT IDLERROLLERS Francisco A. Pico, 1212 N. El Paso St., El Paso, Tex. 79902 [22]Filed: Nov. 19, 1974 [21] Appl. No.: 525,224

[76] Inventor:

[52] US. Cl. 308/20; 308/190 [51] Int. Cl. F16C 35/06 [58] Field ofSearch .1 308/20, 26, 28, 36.1, 190,

Primary Examiner-John J. Love Attorney, Agent, or FirmShanley, ONeil andBaker [57] ABSTRACT A support idler roller for belt conveyors whichincludes a hollow shaft carrying roller bearings and a concentric rollbody made up of a pair of semicylindrical complementary sectionsconcentrically disposed relative to the shaft and supported in spacedrelation to the shaft by the roller bearing structure and an elasticsleeve member having an outer cylindrical wear surface for supporting abelt conveyor resiliently holding the two complementary sectionstogether, the inner bearing raceway member of the roller bearingstructure being rigidly affixed to the shaft and the outer bearingraceway member being frictionally received and held by the body member,the frictional resistance between the outer bearing raceway member andthe body member being such as to permit the body member to turn on theouter bearing raceway member if the roller bearing should freeze.

14 Claims, 3 Drawing Figures Dec. 30, 1975 FIG. I

US. Patent CONVEYOR BELT IDLER ROLLERS BACKGROUND OF THE INVENTION Whereflexible conveyor belts' are used, they are carried on idler rollers,the idler rollers normally rotating on roller bearings. As time passesthe roller bearings cease functioning properly because of infiltrationwith dust and moisture from ore, coal, grain or whatever is beingtransported and resulting uneven wear of the roller elements. Thisresults in the roller bearing structure jamming or freezing. In'suchcase in conventional structures, the idler roller involved stopsrotating and the conveyor belt is dragged over the stopped rollerdamaging the roller surface and the conveyor belt, or the roller turnsand the roller bearing and supporting structure in the roller body ischewed up.

The present invention makes provision for the roller continuing to turnin the event that a roller bearing jams. Although. not as efficient asthe normal roller bearing action, the continued functioning of theroller prevents damage to the roller and to the conveyor belt.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic view in endelevation of a conveyor belt support frame incorporating a plurality ofthe conveyor belt idler rollers of the present invention as they areused to support a belt conveyor.

FIG. .2 is a view in cross section of an idler roller embodying thepresent invention taken on the line 22 of FIG. 3;

' FIG. 3 is a view in cross section taken on the line 3-3 of FIG. 2.

DETAILED DESCRIPTION Referring to the drawing, FIG. 1 shows a conveyorbelt supporting frame indicated generally at made up of a base member 12and two upright standards 14 of tubular configuration, each of whichtelescopically receives a steel cable clamp 16 carrying a set screw 18for clamping and holding an end of a steel cable 20. Steelcable 20 is ofa length which will cause it to assume a catenary form corresponding tothe desired shape of the conveyor belt carrying, for example, acontinuous pile of pulverant material. It will be obvious that insteadof the three idler rollers shown in FIG. 1 for illustration, any numberof idler rollers may be used depending upon the width of the conveyorbelt. Each idler roller has a hollow shaft 22 through which the steelcable passes and each hollow shaft carries a set screw 24 at each end bymeans of which each hollow shaft can be rigidly fastened to cable 20.

As better shown in FIGS. 2 and 3 each idler roller has rigidly mountedon hollow shaft 22 the inner bearing raceway of a roller bearingstructure indicated generally by the reference numeral 32, the tworoller bearing structures being symmetrically arranged along the lengthof hollow shaft 22. Each roller bearing structure 32 includes an outerbearing raceway 34 having an outermost smooth casing 36. Any suitablebearing elements such as ball bearings or roller bearings can be used inthe bearing structure 32 and the term roller bearing is used herein toinclude any satisfactory form of bearing elements.

The idler roller of the present invention has a body member indicatedgenerally at 38 made up of sections, herein shown as two identicalsemi-cylindrical sections 40, 40, which in the form illustrated presenta body member with end flanges 42, 42 and an internal bore of varyingdiameter for purposes described below. The two body member sections 40,40 are resiliently held together by an elastic sleeve 46 which presentsan outer cylindrical wear surface for contact with and support of aconveyor belt, not shown. Sleeve member 46 can be of rubber and theelasticity of this sleeve member is such as to permit it to stretch andpass over flanges 42, herein shown exaggerated in size.

Referring now to the interal bore configuration of body member 38, thereare shown a plurality of circular grooves or recesses concentric to thelongitudinal axis of the shaft, which axis is also the sole axis ofsymmetry of the shaft. Each of two of the circular grooves 50, 50 isshaped to receive snugly the outer smooth casing of one of the bearingstructures 32 so that the pair of bearing structures coact with thecircular slots to hold body member 40 concentric to and spaced fromshaft 22 and against longitudinal displacement of body member 40relative to shaft 22. It will now be evident that body member 40 canrotate around shaft 22 on roller bearing structure 32 when the roller isassembled. Outboard of circular groovesor recesses 50, 50

. are a plurality of similar but narrower circular grooves or recesses52 which hold against longitudinal displacement relative to the shaft aplurality of grease retainers 54 which are snugly but slideably receivedon shaft 22 and within grooves 52;

Body member 38 can be formed of any desirable structural material butfor one of the primary purposes of the present invention this bodymember is formed of any suitable self lubricating material, such asNYLA- TRON, a proprietary material, CS nylon N, a proprietary material,RULON, a proprietary material, or a wear resistant molybdenum disulfidelubricant filled material. The dimensioning of the sections 40, 40 ofbody member 38 and the elasticity of sleeve 46 are such that circulargrooves 50, 50 snugly engage the smooth outer casing 36, 36 of bearing32, 32 and frictionally hold body member 38- against movement relativeto outer bearing raceway 34 during normal operation'of the roller.However, if one of roller bearings 32 fails and, as is usually the case,the bearing jams or freezes, the self lubricating characteristics of thematerial of body member 38 will allow the'body member to rotate on thesmooth casing 36 of the outer bearing raceway member.

Where body member 40 is formed of any desirable structural materialother than a self lubricating material, inserts of self lubricating"material can be used to line recesses 50 whereby the same result isaccomplished at those points as where the entire body member 40 isformed of self lubricating material.

The elasticity of sleeve member 46 is such as to hold the encompassedparts of the roller firmly together but not to exert so great a pressureon juxtaposed surfaces at 36 and 50 as to prevent relative movement ofthese surfaces or too great a frictional force between them.Additionally, the resilient or elastic nature of sleeve member 46permits the encompassed parts of the roller to expand thermally due tofriction at surfaces 36 and 50 when a roller bearing fails.

The roller of the present invention is so designed that it can beassembled by unskilled labor. It requires only the correct positioningof the roller bearings 32 and grease seals 54 in relation to thecomplementary semicylindrical sections 40, 40 of the body, the elasticsleeve 46 being then forced over one end flange 42 of 3 the body bymeans of a pneumatic or hydraulic tool to thereby complete assembly ofthe idler. Thus the design of the roller makes possible a low productioncost.

It is possible with the present invention to continue normal idlerrotation for several years after the roller bearing fails, even afterfailure of the grease and dust seals, because of the great abrasionresistance and low friction properties of the self-lubricating materialengaging casings 36, 36. Therefore, this invention doubles the normallife of conveyor belt idler rollers and completely eliminates damage toa conveyor belt by jammed or frozen roller bearings.

c. a roller body member concentrically disposed relative to the axis ofsymmetry of the shaft means and radially spaced outwardly from the shaftmeans,

d. the roller body member comprising a plurality of separable segmentsextending in the direction of the axis of symmetry,

e. inner bearing raceway means carried by the shaft means innonrotatable relation to the shaft means,

f. outer bearing raceway means disposed in coacting relationship to theinner bearing raceway means,

g. roller bearing means between the inner bearing raceway means and theouter bearing raceway means,

h. elastic sleeve means having an outer cylindrical wear surfacesurrounding and resiliently holding the roller body member segments incontact with the outer bearing raceway means while permitting thermalexpansion of the roller parts, and

i. means associated with the roller body member normally holding theouter bearing raceway means against rotation relative to the roller bodymember,

j. the lastclaimed means including a relatively low coefficient offriction surface means on the roller body member in contact with theouter bearing raceway means, the friction between the relative lowcoefficient of friction surface means and the outer bearing racewaymeans during normal use of 4 movement of the lower coefficient offriction surface means and the outer bearing raceway means.

2. The structure of claim 1 in which k. the separable segments oflimitation (d) comprise a pair of complementary, semi-cylindricalsegments.

3. The structure of claim 2 in which I. the friction surface means oflimitation (j) comprise a self lubricating material at least in thevicinity of the roller body member in contact with each outer bearingraceway means.

4. The structure of claim 3 in which in. there are a plurality of thebearing means defined in limitations (e), (f) and (g) longitudinallyspaced along the hollow shaft means.

5. The structure of claim 4 in which n. elastic sleeve means oflimitation (h) is formed of rubber.

6. The structure of claim 1 in which k. the friction surface means oflimitation (j) comprise a self lubricating material at least in thevicinity of the roller body member in contact with each outer bearingraceway means.

7. The structure of claim 6 in which 1. there are a plurality of thebearing means defined in limitations (e), (f) and (g) longitudinallyspaced along the hollow shaft means.

8. The structure of claim 7 in which in. elastic sleeve means oflimitation (h) is formed of rubber.

9. The structure of claim 1 in which k. there are a plurality of thebearing means defined in limitations (e), (f) and (g) longitudinallyspaced along the hollow shaft means.

10. The structure of claim 9 in which 1. elastic sleeve means oflimitation (h) is formed of rubber.

11. The structure of claim 1 in which k. elastic sleeve means oflimitation (h) is formed of rubber.

12. The structure of claim 2 in which 1. there are a plurality of thebearing means defined in limitations (e), (f) and (g) longitudinallyspaced along the hollow shaft means.

13. The structure of claim 12 in which m. elastic sleeve means oflimitation (h) is formed of rubber.

14. The strucutre of claim 2 in which I. elastic sleeve means oflimitation (h) is formed of rubber.

1. Roller structure comprising a. shaft means having an axis ofsymmetry, b. means for holding the shaft means against rotation relativeto a mounting member, c. a roller body member concentrically disposedrelative to the axis of symmetry of the shaft means and radially spacedoutwardly from the shaft means, d. the roller body member comprising aplurality of separable segments extending in the direction of the axisof symmetry, e. inner bearing raceway means carried by the shaft meansin nonrotatable relation to the shaft means, f. outer bearing racewaymeans disposed in coacting relationship to the inner bearing racewaymeans, g. roller bearing means between the inner bearing raceway meansand the outer bearing raceway means, h. elastic sleeve means having anouter cylindrical wear surface surrounding and resiliently holding theroller body member segments in contact with the outer bearing racewaymeans while permitting thermal expansion of the roller parts, and i.means associated with the roller body member normally holding the outerbearing raceway means against rotation relative to the roller bodymember, j. the last claimed means including a relatively low coefficientof friction surface means on the roller body member in contact with theouter bearing raceway means, the friction between the relative lowcoefficient of friction surface means and the outer bearing racewaymeans during normal use of the roller being greater than the frictionbetween the inner bearing raceway means and the outer bearing racewaymeans but upon abnormally high friction arising between the outerbearing raceway means and the inner bearing raceway means, rotation ofthe roller can continue by virtue of relative movement of the lowercoefficient of friction surface means and the outer bearing racewaymeans.
 2. The structure of claim 1 in which k. the separable segments oflimitation (d) comprise a pair of complementary, semi-cylindricalsegments.
 3. The structure of claim 2 in which l. the friction surfacemeans of limitation (j) comprise a self lubricating material at least inthe vicinity of the roller body member in contact with each outerbearing raceway means.
 4. The structure of claim 3 in which m. there area plurality of the bearing means defined in limitations (e), (f) and (g)longitudinally spaced along the hollow shaft means.
 5. The structure ofclaim 4 in which n. elastic sleeve means of limitation (h) is formed ofrubber.
 6. The structure of claim 1 in which k. the friction surfacemeans of limitation (j) comprise a self lubricating material at least inthe vicinity of the roller body member in contact with each outerbearing raceway means.
 7. The structure of claim 6 in which l. there area plurality of the bearing means defined in limitations (e), (f) and (g)longitudinally spaced along the hollow shaft means.
 8. The structure ofclaim 7 in which m. elastic sleeve means of limitation (h) is formed ofrubber.
 9. The structure of claim 1 in which k. there are a plurality ofthe bearing means defined in limitations (e), (f) and (g) longitudinallyspaced along the hollow shaft means.
 10. The struCture of claim 9 inwhich l. elastic sleeve means of limitation (h) is formed of rubber. 11.The structure of claim 1 in which k. elastic sleeve means of limitation(h) is formed of rubber.
 12. The structure of claim 2 in which l. thereare a plurality of the bearing means defined in limitations (e), (f) and(g) longitudinally spaced along the hollow shaft means.
 13. Thestructure of claim 12 in which m. elastic sleeve means of limitation (h)is formed of rubber.
 14. The strucutre of claim 2 in which l. elasticsleeve means of limitation (h) is formed of rubber.